How to Determine Whether Columns Exist in a Table

Question

Greetings,
Because of customizations to our product, certain database table structures vary between different client installations. Hence, in the code, I need to determine whether two columns exist in a certain table, in order to apply some business logic.
Please suggest a way for me to determine whether two named columns appear in a specific table. In other words, for example, I need to discover whether both columns SAL_GRADE and BONUS appear in the EMP table, or not. Only if both columns are defined, can I apply my business logic.
Thanks,
Avi.

Answer 1

Avi,
Like this ?
SQL> declare
  2    l_count number;
  3  begin
  4    select count(*)
  5      into l_count
  6      from user_tab_columns
  7     where table_name = 'EMP'
  8       and column_name in ('SALGRADE','BONUS')
  9    ;
10    if l_count = 2
11    then
12      dbms_output.put_line('Both columns exist, so apply business logic');
13    else
14      dbms_output.put_line('One or both columns are missing, so don''t apply business logic');
15    end if;
16  end;
17  /
One or both columns are missing, so don't apply business logic
PL/SQL-procedure is geslaagd.Regards,
Rob.